A Generic Synthesis of Transition Metal Oxide Core-Shell Nanowires

A generic nonequilibrium synthesis technique has been developed to produce novel transition metal oxide nanowires, including YBa$_{2}$Cu$_{3}$O$_{6.66}$, La$_{0.67}$Ca$_{0.33}$MnO$_{3}$, PbZr$_{0.58}$Ti$_{0.42}$O$_{3}$ and Fe$_{3}$O$_{4}$. Key to our success is the growth of vertically aligned single-crystalline MgO nanowires, which worked as excellent templates for epitaxial deposition of the desired transition metal oxides and led to high-quality core-shell nanowires. Transport studies on La$_{0.67}$Ca$_{0.33}$MnO$_{3}$ nanowires have revealed the remarkable persistence of metal-insulator transition and magnetoresistance down to nanometer scale. Our technique will enable various in-depth studies such as phase transition in nanoscale oxides and may pave the way for novel applications of these fascinating materials.